law of motion

noun

one of three basic laws of classical mechanics

• Syn: ↑Newton's law of motion, ↑Newton's law

• Hypernyms: ↑law, ↑law of nature

• Hyponyms:

↑first law of motion, ↑Newton's first law of motion, ↑Newton's first law, ↑second law of motion, ↑Newton's second law of motion, ↑Newton's second law, ↑third law of motion, ↑Newton's third law of motion, ↑Newton's third law, ↑law of action and reaction

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1. : a statement in dynamics: a body at rest remains at rest and a body in motion remains in uniform motion in a straight line unless acted upon by an external force — called also Newton's first law of motion

2. : a statement in dynamics: the acceleration of a body is directly proportional to the applied force and is in the direction of the straight line in which the force acts — called also Newton's second law of motion

3. : a statement in dynamics: for every force there is an equal and opposite force or reaction — called also Newton's third law of motion

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Physics.

any of three laws of classical mechanics, either the law that a body remains at rest or in motion with a constant velocity unless an external force acts on the body (first law of motion), the law that the sum of the forces acting on a body is equal to the product of the mass of the body and the acceleration produced by the forces, with motion in the direction of the resultant of the forces (second law of motion), or the law that for every force acting on a body, the body exerts a force having equal magnitude and the opposite direction along the same line of action as the original force (third law of motion or law of action and reaction). Also called Newton's law of motion.

[1660-70]